romanbar – Write roman number with "bars"

‘Bars’, in the present con­text, are lines above and be­low text that abut with the text. Barred ro­man nu­mer­als are some­times found in pub­li­ca­tions.
The pack­age pro­vides a func­tion that prints barred ro­man nu­mer­als (con­vert­ing ara­bic nu­mer­als if nec­es­sary).
The pack­age also pro­vides a pred­i­cate \ifnu­meric.